* This class provides methods to properly format IPv6 addresses for use in URLs
 * by adding brackets where necessary.
 */
public final class IpAddressUtil {

    /**
     * Private constructor to prevent instantiation of utility class.
     */
    private IpAddressUtil() {
        // Utility class - no instances allowed
    }

    /**
     * Determines if the given address string represents an IPv6 address.

        // IPv6 addresses
        assertTrue(IpAddressUtil.isIPv6Address("::1"));
        assertTrue(IpAddressUtil.isIPv6Address("2001:db8::1"));
        assertTrue(IpAddressUtil.isIPv6Address("fe80::1"));
        assertTrue(IpAddressUtil.isIPv6Address("2001:0db8:0000:0000:0000:ff00:0042:8329"));

        // IPv4 addresses
        assertFalse(IpAddressUtil.isIPv6Address("127.0.0.1"));